Inductive-capacitive cyclic charge-discharge ignition system

ABSTRACT

An inductive-capacitive cyclic charge-discharge ignition system includes an ignition transformer primary winding in parallel with a capacitor and fed by an alternating current source providing a plural number of repetition cycles during each igniter firing period. Such repetition cycles cause the capacitor and primary winding to charge and discharge during each of the repetition cycles creating a plurality of ringing periods for each igniter firing period. A diode or an additional capacitor, or both, inserted in series with the parallel combination of the first stated capacitor and primary winding, substantially increases the velocity of arc provided by an igniter. Such arc has several components composed of luminous particles extending across the entire base of the igniter.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation in part of copending application Ser.No. 035,013 filed May 1, 1979 now abandoned.

BACKGROUND OF THE INVENTION

This invention is in the field of ignition systems for fuel burningengines and in particular in such ignition systems which have both acapacitor and an inductive winding of an ignition transformer cyclicallycharged and discharged in discharge aiding mode, and more particularlywherein such system produces a high velocity igniter arc.

The principal prior art ignition systems may be categorized into threegroups. The first category of such prior art systems, referred to as theKettering system, uses a capacitor in series with a primary winding ofan ignition transformer wherein the capacitor is short-circuited by atimer so as to permit the primary winding to be charged by a DC source.The timer then removes the short circuit from the capacitor to permitthe charged winding to discharge into the capacitor so as to create asingle ringing circuit component, used to fire an igniter.

The second category of such prior art systems, referred to as acapacitive discharge system, also has a capacitor in series with anignition transformer winding. Controlled by an appropriate timer, thecapacitor is charged, generally by a higher DC voltage than in theKettering system, such higher DC voltage being generated in the system.The timer then enables the charged capacitor to discharge into thetransformer winding also creating a single ringing current component ofsomewhat higher voltage peak than the Kettering system to fire anigniter.

The third category of such prior art systems involves the use of agenerated AC wave by such prior art system and attempts to apply suchgenerated wave either to an ignition transformer or directly to adistributor in order to fire an igniter.

With respect to the first category, or Kettering prior art system, themain problem lies in the fact that the system attempts to precharge aninductor using a DC source in anticipation of an igniter firing cycle.It is well-known that an inductor energized by DC cannot charge to itsfull current level in a short period of time, and therefore, cannotrapidly produce an induced voltage therein. Hence, only a portion of themaximum current quantity can be made to flow through the primary windingduring the charging mode, with consequent nonuse of the full energystorage capability of such primary winding, and therefore, loss ofelectrical power delivery capability to fire the igniter is experienced.

The current conduction through an inductor powered by a DC source, suchas a battery, when switched on by the timer may be expressed as:##EQU1## where i is current at any instant of time, t is time, V_(dc) isthe voltage provided by the DC source, R is the circuit resistance ofthe inductor and DC source, L is the inductance of the primary windingand R/L is the time constant of the circuit.

From such equation, it can be seen that when t=0, i=0, and when tapproaches infinity, i approaches the value of V_(dc) /R. Based ontypical values of L and R, it would take about 100 milliseconds for theprimary winding to be almost fully charged, and a typical primarywinding charging period is generally not greater than 5 milliseconds.

It is, therefore, obvious that the use of a DC source to charge theprimary winding of the Kettering or first category of ignition systemsis self-defeating in that possibly no more than half the inductor'scharge capacity can be effectively utilized.

With respect to the second category or capacitive discharge system, alike result, with very little improvement over the Kettering system, isrealized.

In such second category system, the higher DC voltage to precharge thecapacitor is obtained by using an electronic oscillator to generate ahigher AC voltage which is then converted to DC by rectification andfiltering. The higher DC voltage is controlled by a timer to prechargethe capacitor and then discharge the capacitor into the ignitiontransformer winding to fire an igniter. If one keeps in mind that acharged capacitor is just like a DC source, then one can apply theforegoing equation which defines current in the transformer winding.Although the value of V_(dc) representing the charged capacitor will behigher than in the case of the Kettering system, one must not lose sightof the fact that the energy content of a charged capacitor is limited bythe capacitance and hence its ability to deliver current for an extendedtime period is limited. Hence, although a higher peak single ringingcycle will result due to the charge from the capacitor being dumped intothe transformer winding, the single ringing period will be substantiallyshortened compared with the single ringing period of the Ketteringsystem.

Since energy is a function of the product of power and time, theadvantage of the capacitive discharge system over the Kettering systemis minimized due to the lesser amount of time during which energy ispresent to fire the igniter.

With respect to the third category of prior art ignition systems or theAC systems, the major problem resides in the inability of the prior artto recognize how to transfer the power from the AC generator to theload, the load generally being a transformer. Consequently, althoughsuch system might basically be able to provide AC power over longerperiods of time, these systems suffer from the lack of technique ineffectively tranferring such power and particularly providing highercurrent levels to the load.

The need for such higher current levels has been repeatedly stated inperiodicals and patents written by those in the automotive manufacturingindustry and in the automotive fuel-producing industry such as Texaco.Such periodicals or patents generally show a high power AC rectangularwave generator employing a transformer wherein one of the windingsthereof is used to saturate the transformer core by employing a DCsource connected to that winding, so as to prevent the generator fromproducing power. A timer, coupled to such winding, enables the core togo out saturation, and ostensibly enables the generator to provide ACpower by magnetic induction through a high voltage winding of thetransformer to an igniter load.

The basic problem with such generator resides in the high impedanceexperienced in the electronic circuit of the generator where thetransistors are located, when under actual load conditions such as whenthe igniter is attempting to arc. Reflected impedance of the highvoltage winding into the lower voltage winding to which the transistorsare connected plus the self-impedance of such lower voltage windingwould severely limit the current circulating in the collector-emittercircuits, and consequently would result in a lowered voltage andseverely reduced current levels deliverable to the actual igniter. Thus,not only is the voltage across the so-called high voltage winding ofsuch prior art AC system lower than expected, but the required highercurrent level for feeding the igniter in order to overcome high pressurefuel-flow across the igniter base, and in particular where theair-to-fuel ratio is in the order of 18 to 1 or greater (lean-burnengines), is not available.

Additionally, such prior art AC systems are inhibited from rapid dutycycling of their AC generator principally by magnetically saturating thegenerator's transformer core to inhibit oscillations. Sight is lost ofthe fact that the DC current used to saturate such core results in acomparatively long time for the core to reach saturation (see formulaabove), and hence slows up the cycling of the generator between itsoperative and quiescent mode. As a result, the prior art AC systemsprovide triangular-shaped current waveforms which inherently have slowrates of change in their waveforms as a function of time and thereforeresult in a reduced induced voltage in the high voltage winding,inasmuch as by Faraday's law of induction, such reduced voltage is afunction of the rate of change of current. It can be appreciated thatif, for example, the prior art could have overcome the above problemsresidual in their AC source and could provide a current waveform outputwith a fast rate of change, such as one approaching a rectangularwaveshape, at least the output voltage of such generator would beincreased. However, the problem of being able to deliver higher currentsto the load would still remain unsolved.

Accordingly, neither the Kettering, capacitive discharge, nor AC systemis capable of delivery of sufficient quantities of energy to fire anigniter, in order to enable the igniter to cause all fuel in an enginecylinder to be consumed and not wasted by failure of the ignition arc toburn same.

A further disadvantage of prior art ignition systems is that they cannotcharge the inductor or transformer winding and the capacitor in a way sothat discharge currents therefrom are additive and aid each other.

A still further disadvantage of the prior art systems is their inabilityto deliver sufficient energy to fire an igniter for extended periods oftime.

Yet a further disadvantage of the prior art systems is their inabilityto deliver more than one ringing cycle during an igniter firing period.

Yet another disadvantage of the precharged inductor or capacitor priorart systems is their inability to rapidly charge the inductor due to useof DC power, with attendant inability to deliver sufficient energy tofire an igniter so as to effectively cause all the fuel to burn duringan igniter firing period.

Yet another important disadvantage of any prior art system is theinability of the system to accelerate the arc luminous particles to suchhigh velocity so that such arc can adequately overcome internal engineand fuelflow pressures. Such prior art systems are therefore unable touse an igniter that develops long arc lengths between its electrodes.Such deficiency results in initation of a small fuel ignited noduleduring the initial ignition period which is insufficient in mass andarea to cause all fuel in a cylinder to be consumed and not wasted.

Other disadvantages with such prior art systems reside in theircomplexity due to the need of a large quantity of electronic componentswhich also gives rise to unreliability as well as high cost ofproduction.

Exemplary of prior art systems is U.S. Pat. No. 3,714,507 which is acapacitive discharge system. A charge retention storage capacitor ischarged by a relatively high DC voltage source, and the charge from thecharge capacitor is discharged through an ignition transformer primarywinding by utilizing a silicon controlled rectifier switch. Anothercapacitor across the primary winding is selected of such value so as tosuppress electromagnetic interference due to discharge of the storagecapacitor.

Another example of prior art is U.S. Pat. No. 3,312,860 which operateson a similar principle to that of U.S. Pat. No. 3,714,507, except thatits high voltage DC power source is of a different design.

Still another example of the prior art is U.S. Pat. No. 3,972,315 whichutilizes two ignition transformer primary windings. One of such windingsis energized by the discharge of a precharged capacitor from a DCsource, whereas the other of these primary windings has a dischargecurrent passing therethrough to combine with the capacitive dischargeinto the first named primary winding. This would be the principle ofoperation if the system were operative, but such system is precludedfrom operation by a hard-wire short circuit across the second namedprimary winding.

All of these exemplary systems miss the major point of technology of notutilizing rectangular or other AC power to feed the ignition transformerprimary winding, and to feed such components as are connected in theprimary winding circuit with AC power, and thus such systems cannotobtain the extremely high energy levels that would otherwise be possiblewhen exciting the ignition transformer primary circuit components withAC power.

SUMMARY OF THE INVENTION

Accordingly, one objective of this invention is to provide an ignitionsystem which would deliver a high energy quantity during each igniterfiring period so that all fuel in the engine cylinder would be ignitedand converted to useful power without passing any unignited fuel intothe engine's exhaust system.

A further objective of this invention is to devise an ignition systemwherein the primary winding of the ignition transformer and a capacitorconnected thereto would be charged in such way so that dischargecurrents from the primary winding and capacitor would be additive so asto increase the energy content fed to the igniter.

A still further objective of this invention is to provide an ignitionsystem having a plurality of chargedischarge cycles of both the primarywinding and capacitor connected thereto during any one igniter firingperiod so as to further increase the energy level fed to the igniterduring such firing period.

Yet another objective of this invention is to utilize a power source tocharge the primary winding and the capacitor connected thereto whichwill enable such primary winding and capacitor to be charged rapidly andfully.

Still another important objective of this invention is to provide anignition system which will develop long arcs across the bases ofigniters and wherein such long arcs, composed of luminous particles,shall have velocities substantially higher than velocities of arcsdeveloped either by a Kettering, capacitive discharge or prior art ACsystems, so as to overcome high internal engine pressures and highpressure fuel-flow past the electrodes of the igniters.

Yet a further object of this invention is to provide highly reliableelectronic circuitry using a minimum number of parts and simple instructure.

Hence, a system is provided which utilizes an electronic repetitive wavegenerator which is electrically duty cycled, and which generatorprovides an output of a plurality of AC waves during each igniter firingperiod.

The primary winding of an ignition transformer is connected in parallelwith a capacitor, and the parallel combination is connected to theoutput of the AC wave generator.

The AC generator waveform output has the ability to charge both thecapacitor and primary winding during each half of each repetition periodof its output waveform. The manner in which the capacitor and primarywinding are charged during each first half cycle of each of thegenerator's repetition periods enables discharge currents from thecapacitor to add to the discharge currents of the primary winding,thereby creating a large amplitude ringing cycle having relatively steepwavefronts during each other half of the generator's repetition periods,resulting in a plurality of ringing cycles with extremely high energycontent delivered to an igniter for firing such igniter during eachigniter firing period.

By inserting either a diode or another capacitor, or both, between theAC generator's output circuit and the parallel combination of theprimary winding and capacitor, the velocity of an arc, created at thebase of the igniter, is substantially increased as compared with the arcvelocity where an igniter is powered by either a Kettering, capacitivedischarge or prior art AC system.

Additionally, the inventive system enables an igniter which is about 250thousandths of an inch in dimension between its arcing electrodes, tocreate an arc which may be as long as 350 thousandths of an inch. Suchdimensions between electrodes is established by removing thegap-adjusting member from a conventional igniter so that arcs can travelbetween the axial electrode and the inner base periphery. Such arclength would be extinguished in prior art igniter systems, even if suchsystems were capable of producing such arcs, due to the high internalengine pressure. However, the increased arc velocity of the inventivesystem, easily overcomes such engine pressure and inhibitsextinguishment of these long arcs, which provides for better fuelcombustion.

The arc phenomena per se is a matter of additional importance. Such arcis comprised of an elongated filament of highly concentrated luminousparticles, which filament extends between the axial electrode and base.The filament is increased in thickness at its ends. Surrounding suchfilament is an envelope of luminous particles of lesser density than thefilament, such envelope having approximately spherically-shapedterminations which will often glow like a light bulb. Under certainvoltage and current conditions, the filament will jump out from itsenvelope and take a path of travel outside the envelope between theaxial electrode and base but generally adjacent to the same radialdirection as the envelope portion-path of travel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an electrical schematic of the ignition system in accordancewith the invention having a switchless output network.

FIGS. 1a, 1b, 1c and 1d are partial schematics of switchless outputnetworks usable in lieu of the switchless output network of FIG. 1.

FIGS. 1e, 1f and 1g are respectively schematic drawings of adisk-contactor timer, a magnetically generating pulse timer and anoptical beam pulse timer, any one of which can be used in lieu of thetimer shown in FIG. 1.

FIG. 2 is a waveform representing the output of an AC generator used inthe system of FIG. 1, 1a, 1b, 1c or 1d.

FIG. 3 is a perspective drawing of a portion of the base of anelectrical igniter showing perspectively the arc phenomena created bythe system of FIG. 1, 1a, 1b or 1c.

FIG. 4 is a drawing of a current waveform in an ignition transformerprimary winding produced by the system of FIG. 1a or 1c, showingmulti-spectra current components associated with each current repetionperiod due to use of diode. Such waveform was observed using a highfrequency oscilloscope.

FIG. 5 is a voltage waveform seen on a high frequency oscilloscopescreen when measured across one-half of a primary winding of atransformer used in the AC generator of the system of FIG. 1a or 1c,showing multi-spectra components created due to diode utilization in theoutput network.

FIG. 6 is an oscilloscopic photograph of the voltage across the primarywinding of the ignition transformer of the system of FIG. 1a or 1cduring igniter firing due to diode utilization in the output network.

FIG. 7 is an oscilloscopic photograph of the current through the primarywinding of the ignition transformer of the system of FIG. 1a or 1cduring igniter firing due to diode utilization in the output network.

FIG. 8 is an oscilloscopic photograph of the voltage across one of thediodes used in the system of FIG. 1a or 1c.

FIG. 9 is an oscilloscopic photograph of the voltage as measured acrossone-half of the primary winding of a transformer used in the ACgenerator of the system of FIG. 1a or 1c due to diode utilization in theoutput network.

FIG. 10 is an oscilloscopic photograph of the voltage across the primarywinding of the ignition transformer of the system of FIG. 1 or 1b duringigniter firing when another capacitor is inserted in series with theparallel combination of a capacitor and primary winding in the outputnetwork.

FIG. 11 is an oscilloscopic photograph of the voltage shown in thephotograph of FIG. 10 depicting a plurality of ringing waveformsexisting in the igniter firing voltage pattern of FIG. 10. The ringingwaveforms were seen in detail by expanding the sweep rate of theoscilloscope time base by a factor of ten.

FIG. 12 is an oscilloscopic photograph of the current through theprimary winding of the ignition transformer of the system of FIG. 1 or1b during igniter firing when an additional capacitor is inserted inseries with the parallel combination of a capacitor and primary windingin the output network.

FIG. 13 is an oscilloscopic photograph of the current shown in thephotograph of FIG. 12 depicting a plurality of ringing waveformsexisting in the igniter firing current pattern of FIG. 12. The ringingwaveforms were seen in detail by expanding the sweep rate of theoscilloscope time base by a factor of ten.

FIG. 14 includes three photoraphic pictures taken of the bases of threeigniters during firing periods of such igniters during operation of thesystem of FIG. 1, 1a or 1d, showing the unusual arc phenomena.

DETAILED DESCRIPTION

Referring to FIGS. 1, 1a through 1g, and 2, an ignition systemdelivering large quantities of electrical energy to an igniter origniters in a fuel combustion engine, employs the principle of creatinga plural number of inductive-capacitive charge-discharge cycles duringany one igniter firing period. Such system is basically simple in itsconfiguration, utilizing a minimum number of electronic components andis highly effective as well as reliable in its operation.

A conventional ground symbol in the drawings refers throughout thisspecification to negative battery potential which is the zero referencelevel for DC or AC voltages or currents, and is also a signal returnpath for AC signals.

Battery 12 provides DC power from its positive terminal 13 to timer 20and to the center-tap of winding 31 of a transformer used in ACgenerator 30.

Timer 20 is activated by means of cam 21 driven by a conventionaldistributor shaft 10 so that contactors 22 and 23 are closed and openedin alternation.

When none of the high portions of cam 21 cooperates with contactor 22,contactors 22 and 23 are closed, and when one of the high portions ofcam 21 cooperates with contactor 22, contactors 22 and 23 are open.Contactor 23 is connected at junction 24 to resistor 25, and resistor 25is connected at junction 26 to positive DC terminal 13 of battery 12.Junction 24 is the point in this timer circuit used to connect to thebiasing circuit of alternating current generator 30, which generatorprovides its waveform voltage output across winding 32, producingoscillations between its minimum levels at B and its maximum levels atA, as shown in FIG. 2.

The purpose of resistor 25 is to provide a positive DC potential to thebias circuit of generator 30 when contactors 22 and 23 are open, andalso to provide a ground or zero potential to such bias circuit whencontactors 22 and 23 are closed without placing a short-circuit acrossbattery 12. The logic provided by timer 20 to circuit 30 may be brieflystated by the following table:

    ______________________________________                                        Contactors  DC Potential   Condition of                                       22 and 23   at Junction 24 Generator 30                                       ______________________________________                                        closed      0              does not                                                                      oscillate                                          open        +              oscillates                                         ______________________________________                                    

Timer 20 was chosen for its simplicity so as to more easily illustrateand explain the switching functions of this system. But it should benoted that a disk-contactor timer, a magnetically generated pulse timeror an optical beam pulse timer as illustrated in FIGS. 1e, 1f and 1grespectively may be substituted for timer 20, if desired.

The FIG. 1 system excludes all diodes, utilizing capacitors 36 and 80.In such case, winding 32 is electrically connected to capacitor 36, andcapacitor 36 is connected to junction 60. Junction 60 is the terminal atwhich primary winding 71 of ignition transformer 70 is connected inparallel with capacitor 80. When timer 20 causes contactors 22 and 23 tobe closed, no energy will be provided by generator 30 and no power willbe delivered to winding 71 and capacitor 80. But when timer 20 causescontactors 22 and 23 to open, winding 32 will excite such parallelcircuit with AC energy. Since high voltage output cable 75 is normallyconnected to rotor 165 of a conventional high voltage distributor 160having stationary members 166 which are connected to electrodes 120 ofigniters 150 in a multiple igniter ignition system, or cable 75 isconnected directly to an igniter's electrode 120 in a single ignitersystem utilizing igniter 150, in both instances the electricallyconductive base 130 being at ground potential, the impedance lookinginto primary 71 will also include the reflected impedance due tosecondary 72 feeding an arcing igniter.

High AC current flow is transferred from winding 31 to winding 32 ofgenerator 30 by virtue of the inclusion of capacitor 36. Deletion ofcapacitor 36 will reduce the current flow through primary winding 71 andwill also reduce the arc velocity.

The AC current flowing into junction 60 due to the AC voltage acrosswinding 32 is represented by arrow 61, such current dividing intocurrent component 62 which charges primary winding 71 and currentcomponent 63 which charges capacitor 80, so that one terminal ofcapacitor 80 is charged positively, as indicated. These charging currentcomponents are initiated during the conductive portions of each cycle ofFIG. 2 such as represented by numeral 91 for every such half-cycleperiod.

It must be remembered that the AC voltage fed to winding 71 andcapacitor 80 results in primary winding 71 and capacitor 80 beingrapidly and completely charged. It should also be noted that the FIG. 2waveform, by virtue of its rapid charging ability, avoids thedisadvantage inherent in a conventional ignition system utilizing DCpower, where such DC power slowly charges the primary winding of anignition transformer.

It should be remembered that, once charged, such winding 71 andcapacitor 80 will remain charged during the flat or constant voltageportion of the conductive half-cycle period 91 of the wave of FIG. 2, atthe maximum level. When something happens to disturb the circuitequilibrium, such as the forcing voltage function across winding 32feeding these components suddenly going through a transition state suchas at t₁, to cause the FIG. 2 voltage to drop to its minimum level,discharge currents from winding 71 and capacitor 80 will start to flowas denoted by dashed arrows 64 and 65 respectively. The dischargecurrent flow from an inductor will continue in the same direction as itscharge current direction flow, but the discharge current from acapacitor will have a direction reverse to its charge current direction,thereby aiding the discharge current in the inductor.

Consequently, between time t₁ and t₂, discharge current component 64from winding 71 will initiate its flow direction in the same directionas its charge component 62, but discharge current component 65 fromcapacitor 80 will initiate its discharge flow in opposite direction toits charge component 63, as indeed it has to, since current component 65must start flowing in a direction away from the capacitor's positivelycharged terminal. Hence, the discharge component 65 flowing throughjunction 60 will be additive to the discharge component 64 therebyincreasing the current flow through primary winding 71. The samecharging process will be repeated during period t₂ -t₃, and the samedischarge process will be repeated during period t₃ -t₄ for the secondcycle as well as for subsequent cycles beyond time t₄, during any oneigniter firing period, to add the capacitor discharge current to theinductor discharge current for each cycle of FIG. 2 waveform inappositeto prior art systems which only depend upon charging either an inductoror a capacitor.

It should be realized that the discharge action causes ringing typeoscillation of the parallel circuit comprising inductive winding 71 andcapacitor 80, by virtue of discharge current components 63 and 65circulating in winding 71 and capacitor 80. Hence, such ringingoscillation will occur during each quiescent wave portion 92, therebyproviding a plural number of ringing cycles in sequence during any oneigniter firing period. Each ringing oscillation will have both positiveand negative excursions or be bipolar in character. At an average enginespeed of 3,000 revolutions per minute for a four-cylinder engine havinga 45 degree dwell period, an igniter would fire for approximately 5milliseconds during which time 15 ringing cycles would be experienced.At the engine idling speed, about 45 ringing cycles per igniter firingwould be experienced, and at starting speeds as much as 100 or moreringing cycles would occur, thereby facilitating starting the engine.All these ringing cycles per igniter firing may be compared with thesingle ringing period at substantially lower voltage and current levelsprovided by a conventional ignition system, in order to appreciate theadvantages afforded by this functionally high energy but structurallysimple ignition system.

A major benefit contributed by the system shown in FIG. 1 is itsswitchless output network, wherein no switch either of the electronic orother type exists. Such output network consists of primary winding 71 inparallel connection with capacitor 80, and the parallel combination inseries with capacitor 36 which is also in series with output winding 32of AC generator 30.

Alternating current generator 30 provides AC voltage excursions acrosswinding 32 as symbolically illustrated by the waveform of FIG. 2. Suchvoltage excursions represent the actual voltage pattern when a resistiveload is connected across winding 32. A similar rectangular waveform tothat shown in FIG. 2 would represent the current excursions throughwinding 32 and such resistive load. When the load connected to winding32 is reactive, as herein, and when generator 30 bias current is keyedon and off, the voltage output from generator 30 will have transientspikes. However, in explaining the theory of operation of this system,the waveform without transient spikes, as shown in FIG. 2, will beassumed.

It may be seen that generator 30 supplies a voltage output across itswinding 32 which is referenced to ground, the common signal return pathfor both AC and DC voltages and currents, as well as the commonreference point for the electrical igniters used herein. Such voltagerises from the ground reference level which is also its minimum level atB to its maximum level at A, and then stays at the maximum level forone-half cycle. At the end of such half-cycle, the voltage falls to itsminimum level staying at the minimum level at B for the otherhalf-cycle. These cyclic excursions are repeated a plural number oftimes for any one igniter firing period.

Although a rectangular waveshape is illustrated in FIG. 2, it is pointedout that any waveshape, regular in form or complex, may be utilized inthis invention as long as the waveforms are AC in nature.

It should also be noted that winding 32 could be connected to positiveDC terminal 13 of battery 12 instead of ground, in which case thewaveform of FIG. 2 would be shifted upward by the voltage value ofbattery 12. However, making such connection, though seemingly harmless,may bring about a reduction in the voltage output to theinductive-capacitive load herein, since the timer contacts are closedwhen the AC generator is delivering power to the load. In such case,resistor 25 would consume part of the voltage generated. If, on theother hand, resistor 25 is not electrically across battery 12 whengenerator 30 generates its voltage output, then the series combinationof resistor 25, resistor 34 and the base-to-emitter junction of eitherof transistors Q is effectively across battery 12 to also deprive theload of some of the voltage across winding 32 developed by generator 30.Either of these conditions could exist with winding 32 terminated on oneend at terminal 13. When transistors Q are of the PNP-type, generator 30provides oscillations during the periods when contactors 22 and 23 areclosed, or as here, when such transistors are of the NPN-type, generator30 provides oscillations when contactors 22 and 23 are open. However,always terminating one end of winding 32 at ground potential avoids theloss of voltage generated by generator 30, no matter which type oftransistors are used.

It may be noted that the voltage waveform across winding 32 is shown asa rectangular wave with cyclic excursions between the minimum andmaximum levels. The minimum level at B may be regarded as the negativeexcusion of the FIG. 2 waveform and the maximum level at A may beregarded as the positive excusion of such waveform.

Such waveform almost resembles an ideal series of half-wave rectifiedsignals. The advantage of using such waveform, even if it is changed inshape by use of an inductive-capacitive reactive load and is thereforeno longer rectangular in shape, is that it is possible to cyclicallycharge and discharge the inductive-capacitive load components during anyone cycle or repetition period of such wave without the need of anyadditional control components. Such advantage contributes to circuitsimplicity with accompanied advantage of being able to generate amultiplicity of ringing oscillation periods during any one igniterfiring period so as to very substantially increase the power and energydelivered to an igniter during its firing period.

When timer 20 keys generator 30 to its oscillatory mode by openingcontacts 22 and 23 so as to provide a positive DC bias voltage to thebases of power transistors Q via feedback winding 33, base current iscaused to flow through resistor 34 and through the base-emitter junctionof one of the transistors Q. The circuit composed of one of transistorsQ and one-half of winding 31 fed by +DC at its center tap will thereuponhave collector current flowing therethrough in alternation with theother half of winding 31 and the other transistor Q via their respectivecollector-to-emitter junctions to ground so as to create the oscillatorywaveform of FIG. 2. Though transistors Q are of the same type, eachtransistor has sufficiently slightly dissimilar characteristics so thatone or the other transistor will draw collector current first to startthe oscillation process. This type of oscillatory circuit is generallyknown in the art as a Royer oscillator, although generator 30 herein hasbeen simplified over the original Royer circuit. Generator 30 has beenutilized in applicant's allowed patent applications, serial number960,871 filed Nov. 15, 1978, serial number 969,075 filed Dec. 13, 1978,and serial number 962,754 filed Dec. 14, 1978. Reliability has also beenadded to generator 30 by component reduction and by including dutycycling of such generator by switching its bias current on and off. Suchswitching enables operation of the transistors about half the timeduring a firing cycle so as to prevent their overheating and therebyimprove their reliability and extend their operating life.

A single cycle of the waveform of FIG. 2 is composed of a periodextending from t₀ to t₂ having a conductive portion 91 and a quiescentportion 92. Portion 91 is termed conductive since it is the half-cycleperiod during which time, voltage is provided by generator 30 to chargeinductor 71 and capacitor 80. Portion 92 is termed quiescent since it isthe half-cycle period during which time, generator 30 does not provideany output and consequently it is the cyclic portion during whichinductor 71 and capacitor 80 will discharge to effect a ringing currentcomponent of decreasing amplitude and also of decreasing frequency.Keeping in mind that ringing action occurs during every cycle ofrectangular wave output from generator 30, it is conceivable that anyone ignition firing period may have about 60 ringing current cycles, ascompared with a single ringing current cycle in a typical prior artignition system.

Hence, when contactors 22 and 23 are initially opened for any oneigniter firing period, the voltage across winding 32 rises from itsminimum level at t₀ to its maximum level and remains substantiallyconstant at the maximum level for the first one-half cycle, which is theconductive portion of that cycle, until time t₁. At t₁, the voltagedrops to the minimum level and remains at the minimum level until timet₂ for the other half of the first cycle, which is the quiescent portionof that cycle. At t₂, the waveform starts again to rise to the maximumlevel to stay there until time t₃, at which time the voltage again dropsto the minimum level and remains at the minimum level until time t₄,which is the end of the second cycle. Accordingly, during eachconductive portion 91 of any given cycle, winding 71 and capacitor 80are charged, and such charged components discharge during each quiescentportion 92 of the same cycle.

The rate or frequency of oscillation of generator 30 is dependent upondesign of the transformer used in generator 30, but generally from 2,000to 3,000 cycles or repetition periods per second has been foundsatisfactory for this ignition system. Consequently, the number ofcycles or repetition periods, as exemplified by the two cyclesillustrated in FIG. 2 waveform, will depend on the length of timecontactors 22 and 23 stay open. When contactors 22 and 23 are closed,the zero bias provided to winding 33 of generator 30 will cut offoscillation and no output will be provided at 32. In other words, novoltage waveform as in FIG. 2 will be present across winding 32 whencontactors 22 and 23 are closed.

FIG. 1a modifies the switchless output network of the system shown inFIG. 1 and as above discussed. Such modification of the outputswitchless network is in terms of using diode 40 in lieu of capacitor36. As will be shown below in conjunction with the discussion of theoscilloscopic photographs, diode 40 also contributes a multiplicity offrequencies by its presence in the output network, causing ignitioncurrent flowing through primary winding 71 to be rich in suchfrequencies.

FIG. 1b modifies the switchless output network of the system shown inFIG. 1 and as above discussed. Such modification of the outputswitchless network is in terms of using diode 50 by connecting samebetween junctions 60 and 74. The basic performance of the output networkof this figure is similar to that of FIG. 1 inasmuch as capacitor 36 isthe component mostly contributing to the waveforms of current andvoltage through and across winding 71.

FIG. 1c modifies the switchless output network of the system shown inFIG. 1 and as above discussed. Such modification of the outputswitchless network is in terms of using diode 40 in lieu of capacitor36, and also the inclusion of diode 50 between junctions 60 and 74. Theprincipal function of diode 50 is to permit charging current 62 to flowthrough winding 71 but to inhibit winding 71 from loading down capacitor80 and preventing premature partial discharge of such capacitor.Otherwise, the operation of the system with this output network issimilar to the operation of the system utilizing the network of FIG. 1a.

FIG. 1d modifies the switchless output network of the system shown inFIG. 1 and as above discussed. Such modification of the outputswitchless network is in terms of deletion of capacitor 36 so thatwinding 32 is connected directly to the parallel combination of primarywinding 71 and capacitor 80. Use of this output network reduces theignition primary current flow and igniter arc velocity as compared withthe output network as used in FIG. 1, 1a, 1b or 1c.

It should be noted that diodes 40 and 50, capacitors 36 and 80, primarywinding 71 and output winding 32 are all passive components since theydo not internally generate electrical energy, and any electrical energytherein has to be supplied to these components. Inapposite, transistorsor oscillators are active electronic components since they cancontribute signal energy.

FIG. 1e illustrates a disk-contactor timer at 170, wherein disk 171 isof electrically conductive material and at ground potential by virtue ofbeing affixed to engine distributor shaft 10 which is at groundpotential. Disk 171 has electrically insulative members 172 regularlyspaced at its periphery within the disk confines. The periphery of thedisk is in cooperation with contactor 173 which has a resistor 175 inseries therewith, the resistor being connected to a positive DC terminalat 13 of FIG. 1, instead of timer 20. Junction point 174 is connected tobias resistor 34 so that this timer can perform the same functions astimer 20. The logic provided by timer 170 is briefly stated in thefollowing table:

    ______________________________________                                        Contactor 173  DC Potential Condition of                                      Cooperating With                                                                             at Junction 174                                                                            Generator 30                                      ______________________________________                                        conductive     0            does not                                          portion of                  oscillate                                         disk 171                                                                      member 172     +            oscillates                                        ______________________________________                                    

FIG. 1f illustrates a magnetically generated pulse timer at 180, whereinmagnetic reluctor wheel 186 is driven by engine distributor shaft 10. Apositive DC potential is provided to this timer from juction 13 of FIG.1, so that this timer is connected to such junction instead of timer 20.A voltage divider resistive network 181 and 182 provides approximately+1.2 volts DC to coil 185, wound on permanent magnet core 183. Core 183has a magnetic pole piece 184 for enabling magnetic flux to be inducedin coil 185 by virtue of magnetic protrusions 187, integral withreductor wheel 186, being driven past pole piece 184 due to shaft 10being driven by the engine. The other end of coil 185 is connected tothe base of transistor Q1. Transistor Q1 has resistor 188 connectedbetween its collector and junction 13. The emitter of Q1 is at groundpotential, and the collector of Q1 is connected to bias resistor 34 ofFIG. 1. When reluctor wheel 186 is at standstill, the base of transistorQ1 is at positive DC potential and Q1 conducts, thereby lowering thecollector of Q1 to ground potential and inhibiting oscillation ofgenerator 30 by virtue of zero bias being applied to the bases oftransistors Q. When reluctor wheel 186 is driven by shaft 10 and whenprotrusions 187 are driven past pole piece 184, a negative-going spikeis induced in winding 185, which spike is sufficient to overcome thepositive DC potential at the base of Q1, thereby lowering the base of Q1to a negative potential and stopping conduction of Q1 which raises thecollector potential of Q1 to a positive value thereby applying a +DCbias voltage to bias resistor 34 of FIG. 1 and causing generator 30 tooscillate. The following table briefly shows the logic imposed by timer180 upon the FIG. 1 system.

    ______________________________________                                        Protrusion                                                                             Potential at                                                                            Condition DC Bias of                                                                            Generator                                187      Base of Q1                                                                              of Q1     Bases of Qs                                                                           30                                       ______________________________________                                        not driven                                                                             +         ON        0       does not                                 past pole                            oscillate                                piece 184                                                                     driven past                                                                            -         OFF       +       oscillates                               pole piece                                                                    184                                                                           ______________________________________                                    

FIG. 1g illustrates an optically generated pulse timer 190 which isconnected to FIG. 1 in like manner as timer 20 but in lieu thereof.Timer 190 comprises an optically opaque disk 191 driven by distributorshaft 10. Disk 191 has a number of apertures 192 regularly spaced fromeach other at the disk periphery. A lamp or light-emitting diode 193 isconnected to +DC potential at 13, and light-activated transistor switchQ2 has its collector connected to +DC potential at 13, the emitter of Q2being connected to resistor 195 and the other side of resistor 195 beingat ground potential. The emitter of Q2 is connected to bias resistor 34of FIG. 1, so that this timer can bias generator 30 instead of timer 20.When disk 191 is driven so that its opaque portion blocks light beam 194emanating from lamp 193, the base of Q2 is effectively at zero potentialand Q2 does not conduct thereby causing its emitter to be at ground orzero potential and biasing resistor 34 to zero potential therebyinhibiting oscillation of generator 30. When disk 191 is driven to aposition so that one of apertures 192 permits passage of light beam 194therethrough to impinge on the base of Q2, the base of Q2 is raised to apositive potential which causes Q2 to conduct, thereby raising itsemitter to a positive potential and biasing resistor 34 to a positive DCpotential to cause generator 30 to oscillate. The logic provided bytimer 190 may be briefly stated by the following table:

    ______________________________________                                        Disk 191 Driven         Emitter                                               So That Light                                                                             Condition   Potential Generator                                   Beam 194    of Q2       of Q2     30                                          ______________________________________                                        cannot impinge                                                                            OFF        0          does not                                    on base of Q2                     oscillate                                   impinges on ON         +          oscillates                                  base of Q2                                                                    ______________________________________                                    

FIG. 3 is representative of the arc phenomena either when diodes 40and/or 50 are in circuit, when capacitor 36 is in circuit, or whencapacitor 36 and diode 50 are in circuit.

A portion of igniter base 130 is illustrated in FIG. 3 showing itsthreaded part and particularly the inner periphery of such electricallyconductive base 130. Axial electrode 120 which is common to igniters isembedded in ceramic insulator 140, the firing end of electrode 120protruding from insulator 140.

The igniter is shown generally at 150 and such numeral also identifiesthe high velocity arc that is created by the systems used to fire theigniter. Such arc appears to comprise an elongated core or filament ofconcentrated luminous particles 151 having spread-out terminations 152and 153 at both the axial electrode and inner base peripheryrespectively. An aura of lesser concentration of luminous particles 155surrounds core or filament 151, the ends 152 and 153 thereof beingsurrounded by enlarged spherical-like aura of luminous particles 156 and157 respectively of such lesser particle concentration. The reason forboth the spread-out ends 152 and 153 and the enlarged spherical aura 156and 157 surrounding such ends respectively appears to be due to the highimpact of these luminous particles upon the electrode and inner baseperiphery in view of the high velocity with which these luminousparticles travel between such two points of the igniter base. One cananalogize this phenomena to a bullet which spreads upon impact with asolid object due to the high bullet velocity, and the high density ofthe object which the bullet cannot penetrate upon impact, even due toits high velocity.

In either the situation using capacitor 36 or any of the diodes incircuit, or both, when the power delivered to generator 30 was droppedby reducing the voltage from battery 12 which energizes generator 30,arc filament 151 appeared to jump out from its position surrounded bythe lesser concentrated luminous particles, to a position at 151'whereupon it followed the general contour of insulator 140 to terminateat inner periphery 130 at approximately the same location as when suchfilament had an arc locus as at 151. During change of locus from 151 to151' the lesser concentrated luminous particle mass remainedsubstantially unchanged.

It should be noted that the overall high arc velocity is evidenced byaudible sounds occurring upon arc impact at 120 or 130, such audiblesounds being not much lower in intensity under the arc locus 151'condition as compared to the arc condition locus at 151.

In either case, one important feature of this unusual arc configurationwith its high velocity is that igniters can be used that have 250thousandths of an inch radial spacing between its arcing members toproduce long arcs which will not be extinguished by the high internalengine pressures, and thereby totally and efficiently burn and convertall the fuel to useful engine power without wasting a good percentage ofsuch fuel.

The oscilloscopic patterns for voltage and current of FIGS. 6 and 7respectively, created by the system of FIG. 1a utilized diode 40. It isdifficult to visually see individual ringing periods of these patternsin view of the fact that use of a diode in circuit with winding 32 andwith inductor 71 and capacitor 80, gives rise to multi-spectra bands offrequency components containing many overlapping ringing components.Such overlapping ringing components may be seen when utilizing the mostrapid sweep rate on the 50 megacycle oscilloscope, used to observe thesephenomena. However, such overlapping ringing components or periods aretoo low in intensity to enable them to be photographically captured.Since a fast oscilloscope time base sweep rate will disclose themulti-spectra frequency bands for each charge-discharge cycle, suchspectra was carefully observed and copied in the drawings as shown inFIGS. 4 and 5.

FIG. 4 shows the current wave in primary winding 71 when using aten-times expanded sweep of a portion of one of the current waveforms ofFIG. 7. The dominant current excursions of 8.3 amperes as shown in FIG.7 are denoted in FIG. 4 as waveforms 101. The hairlike patterns at thelower extremes of the waveforms of FIG. 7 are denoted in FIG. 4 at 102.Such hairlike patterns are the principal multi-spectra bands 102existing for each dominant current excursion 101 as shown in FIG. 4.Additionally, FIG. 4 shows a single perturbation at 100, at thebeginning of the current waveform, and also shows other spectralfrequency groups 103 associated with and extending upward from thepositive half of each current cycle of such waveform. Such spectra 103are not photographically capturable in FIG. 7 in view of the low lightintensities on the oscilloscope screen. Such spectra 103 also providegroups of ringing cycles, but in lesser quantity than spectral groups102. It should be pointed out that the respective heights of spectralgroups 102 and 103 is unknown inasmuch as these amplitudes appeared tocontinue on the face of the oscilloscope screen well beyond theoscilloscope's vertical beam shifting control capability. It would notbe unreasonable to state that each group 102 and 103 spectra mayrepresent current swings in excess of 100 amperes, though atcomparatively low duty rates.

In the system of FIG. 1a, utilizing diode 40, the voltage excursionsduring igniter firing as shown in FIG. 6, do not appear to illustratemulti-spectra bands such as 102 or 103. The lack of such spectral bandsin the voltage pattern is not fully understood.

The fact that the multi-spectral bands exist in the current pattern ofthe system of FIG. 1a, which utilizes a diode, is also evidenced by thepatterns of FIGS. 5, 8 and 9.

FIG. 8 is an oscilloscopic pattern of the voltage across diode 40. FIG.9 shows the presence of the FIG. 8 oscilloscopic pattern carried on topof the voltage waveform as measured across one-half of winding 31. FIG.5 is the waveform of FIG. 9 as observed on the oscilloscopic screen whenthe time base sweep rate of the oscilloscope was ten-times expanded.Since FIGS. 5 and 9 represent voltages across winding 31 and since FIG.8 shows the voltage across diode 40 in series with winding 32, whichvoltage induced in winding 32 is opposite in phase to the phase of thevoltage induced in winding 31, the phases of these patterns can beexpected to be reversed since such voltages are measured at twodifferent windings of a transformer. It is therefore obvious that FIG. 8pattern is due to the same cause that creates the pattern riding on topof the dominant waveform in FIG. 9. The contribution due to diode 40 isabout 60 percent in peak amplitude of the total waveform in FIG. 9 inwhich the dominant pattern is only 40 percent of such total amplitude.

Examining the ten-times expanded waveform of FIG. 9, as shown in FIG. 5,it can be seen that the dominant pattern of such waveform will startwith a distorted rectangular wave portion 106 followed by a pluralnumber of similarly-shaped distorted sinusoids 105. This wave willexhibit positive spectra groups starting with spectrum 107 which has thehighest amplitude, followed by spaced spectral groups 108 through 115 ofdecreasing amplitudes. Each spectral group will contribute to theringing spectral groups discussed above in connection with FIGS. 4 and7.

Examining FIG. 1b, it should be noted that negative components ofringing periods can flow through winding 32 even with a diode such asdiode 50 effectively connected in series with winding 71 betweenjunctions 60 and 74, in view of the fact that negative ringing currentportions will flow in direction from cathode to anode of such diodes.The fact such diode contributes to the multi-spectra bands is easilyshown by short-circuiting such diode, whereupon the spectralcontributions shown in FIGS. 4, 5, 7, 8 and 9, disappear.

Consequently, in FIG. 1c, to inhibit ringing components having positivecurrent directions from flowing through winding 32 during the dischargeof capacitor 80 and winding 71, diode 40 is utilized. Diode 40 willoppose positive components of discharge currents 64 and 65 from flowingthrough junction 60 into winding 32 and force positive components ofdischarge current 65 to flow in the same direction as as the flow ofpositive discharge current component 64, namely, through capacitor 80and winding 71, thereby aiding each other and increasing the powerapplied to any igniter. Additionally, the use of diode 50 in conjunctionwith diode 40, produces excellent results. Diode 50 is effectively inseries with winding 71 as part of the inductive load portion of thesystem.

Importantly, it should be noted that the use of diode 40 alone or incombination with diode 50 results in substantial increase in velocity ofarc firing across the igniter base. Photographic results of such firingare depicted at 161, 162 and 163 of FIG. 14. Igniter 161 has an 18millimeter base and shows the arc between its center electrode andperiphery of the base. Such arc is of dumbbell-shape having a thick bodyportion and enlarged generally spherically-shaped ends at both thecenter electrode and inner wall of the base. Such enlarged arcterminations are due to the arc molecular impact resulting from thehighly unusual arc velocity upon the center electrode and base. The arcimpact is at dual points in view of the alternating current or bipolarringing cycles obtained by this system. Igniter 162 has a 14 millimeterbase and also shows a similar arc to that of igniter 161. Igniter 163also has a 14 millimeter base wherein two such arcs were photographed intwo successive igniter firing periods on the same photographic plate.Since it was difficult to synchronize the camera shutter with theincreased arc velocities, the shutter was opened for a relatively longperiod of time so that the arc could be photographed when it occurred,and in the case of igniter 163, by the time the shutter was closed, twosuch arcs were photographically recorded.

The photographs of the arcs in FIG. 14 are too small to gain anappreciation of their structure and functional characteristics. Hence,such arcs were observed over long periods of time, and a representationof one such arc was drawn in a detailed and enlarged view in FIG. 3.

Referring to FIGS. 1, 1a, 3 and 10 through 14, and for the purpose ofphotographing the phenomena in FIGS. 10 through 13, the FIG. 1 systemdid not make use of diodes. Such FIG. 1 system did utilize capacitor 36.The transformer in generator 30 was also changed to one providing ahigher turns ratio of windings 32 to 31, which accounted for theincreased primary valtage and current exhibited in FIGS. 10 through 13patterns. The use of capacitor 36 instead of any diode such as diode 40,resulted in the same types of arcs as shown in FIGS. 3 and 14, asdiscussed above in connection with diode usage, but the electricalvoltage and current patterns as in FIGS. 10 through 13 clearly showedthe multiplicity of ringing cycles for any one igniter firing period. Itshould be noted that the same result obtained when, after taking thephotographs of FIGS. 10 through 13, diode 40 was added to the circuit ofFIG. 1 in series with capacitor 36, showing that in the circuitutilizing capacitor 36, such capacitor was the controlling componentwhen both the capacitor and diode were utilized.

Capacitor 36 either avoids the creation of multi-spectra bands as whendiodes were used, or when used in conjunction with one or more of thesediodes, acts as a filter for such multi-spectra bands as created by thediodes. Without any of the diodes in the circuit, but with capacitor 36in the circuit, such capacitor also represses some of the very highfrequency components, making it possible to clearly see the multipleringing cycles in the oscilloscopic patterns of FIGS. 11 and 13.

FIG. 10 shows 1,000 volts peak-to-peak developed across the primary 71and shows two successive igniter firing periods. The pattern resultingin FIG. 11 is by virtue of a ten-times expanded time base of the timebase sweep of the oscilloscope, as compared with the sweep rate used toobtain FIG. 10, so that only a fractional part of one of the igniterfiring periods of FIG. 10 may be seen as expanded in FIG. 11, showing aplural number of sequential voltage ringing cycles, each having bipolarringing excursions. Each ringing cycle was generated by the charge anddischarge phases during respective conductive and quiescent portions 91and 92 of the waveform of FIG. 2, as provided by generator 30.

Some of the ringing cycles for one ignition firing period of the voltagepattern of FIG. 10 may be clearly seen in the ten times expanded timebase of pattern shown in FIG. 11, while some of the ringing cycles forone ignition firing period of the current pattern of FIG. 12 may beclearly seen in the ten times expanded time base of the pattern shown inFIG. 13.

FIG. 12 shows a current through primary winding 71 of 10 amperespeak-to-peak during each of the same two successive igniter firingperiods as in the case of the voltage pattern of FIG. 10. Currents up to16 amperes were obtained, dependent on the transistors used and thedesign of the transformer of generator 30. The current ringing cycles asin FIG. 13 when observed on the face of the 50 megacycle oscilloscopedisplayed thin high frequency spectral lines in both positive andnegative directions, repeating about every quarter cycle, but suchspectral lines were difficult to capture photographically in view oftheir low optical intensity.

FIG. 14, the illustration of igniter bases 161, 162 and 163, with theirrespective arcs, also represents the arcs created due to the use ofcapacitor 36 in lieu of any of the diodes, or jointly with the use ofany of the diodes.

Referring to ALL FIGURES, in the laboratory test set up of this system,a conventional distributor was motordriven by driving shaft 10 thereofat a speed comparable to an engine's 3,000 revolutions per minute. Thedistributor had four igniter ports so that four igniters were fired insequence. The gap-adjusting members from each of the igniters wereremoved so that the generated arc could fire between the axial electrode120 and the inner periphery of the igniter base 130. Igniters having 18and 14 millimeter diameter bases were used. Therefore, the arc lengthsat 150, between the axial electrode and base, ranged between 250 and 350thousandths of an inch in length.

The contactors in the experimental distributor, analogous to contactors22 and 23 of timer 20, were set so that they were opened and closed for5 millisecond periods each when the distributor shaft was driven at arate of speed comparable to an engine speed of 3,000 revolutions perminute. Such firing period would be the same as in an actual automotivefour-cylinder engine driven at 3,000 revolutions per minute representingaverage engine speed, wherein the dwell time of the contactors in thedistributor would be set to be equal to their non-dwell time.

The measurements of voltage and current were made using an accuratelycalibrated Hewlett-Packard 50 megahertz oscilloscope. The current wasmeasured by utilizing a one-ohm high power resistor in series withwinding 71 and measuring the voltage across the one-ohm resistor usingthe calibrated oscilloscope. The voltage across winding 71 and capacitor80 was measured by using a high resistance voltage divider acrosswinding 71 substantially higher in resistance than the impedancepresented by the parallel combination of winding 71 and capacitor 80, soas to effect reasonably accurate voltage readings across the lowerresistance portion of such voltage divider. The fact that the voltagedivider was of sufficiently high resistance value to enable making suchmeasurements was determined by observing that the voltage oscilloscopicpattern did not decrease in amplitude when such voltage divider wasconnected across winding 71. The need for such voltage divider was dueto the fact that the internal attenuators of the oscilloscope were inthemselves not sufficient to reduce the actual voltage excursions so asto bring the entire peak-to-peak voltage envelope within the confines ofthe face of the oscilloscope's cathode ray tube.

Without diode 40 or capacitor 36 in the output network as shown in FIG.1d switchless output network, the large arcs developed across the basesof the igniters did not appear to exhibit as high a velocity as with theuse of such diode or capacitor. With such diode or capacitor in theswitchless output network the velocity of such arcs increaseddramatically, developing sounds comparable to the cracking of a whicp oreven lightning discharge sounds. With such diode or capacitor in theoutput network the high velocity are excursions between axial electrode120 and base 130 of igniter 150 were accompanied by spheres of flashinglight at the extremities 152 and 153 of the arc pattern.

What is claimed is:
 1. An inductive-capacitive cyclic charge-dischargeignition system for providing a plurality of ignition periods,comprising the combination of:an ignition transformer having a primarywinding; a capacitor connected to the primary winding and forming aparallel circuit with said primary winding; AC generating means havingan output winding in series with said parallel circuit for powering saidparallel circuit with AC energy during each said ignition period, saidoutput winding and parallel circuit forming a passive switchlessnetwork; and timing means coupled to said AC generating means forcontrolling DC bias current to said generating means so as to duty cyclesaid generating means.
 2. The system as stated in claim 1, including:asecondary winding of said ignition transformer coupled to the primarywinding; and at least one electrical ignition means having anelectrically conductive tubular base and an electrode insulated fromsaid base intermittently coupled to the secondary winding for producingan electrical arc having an elongated filament composed of luminousparticles and a mass of luminous particles of lesser density than saidfilament that surrounds said filament between said electrode and baseduring each said ignition period.
 3. The system as stated in claim 1,wherein said timing means constitutes a cam-actuated pair of contactors.4. The system as stated in claim 1, wherein said timing meansconstitutes an electrically conductive disk having electricallyinsulative members regularly spaced at the periphery of and within theconfines of said disk and an electrically conductive contactor incooperation with said periphery.
 5. The system as stated in claim 1,wherein said timing means is a magnetically generated pulse timer. 6.The system as stated in claim 1, wherein said timing means is anoptically generated pulse timer.
 7. A method for producing electricalignition power during each ignition period of an ignition system,comprising in combination the steps of:(a) duty cycling an AC generatorso as to produce AC energy during each ignition period; (b) charging acapacitor and a primary winding of an ignition transformer in parallelwith the capacitor during one-half cycle of said AC energy via an outputwinding of said AC generator, said output winding and parallelcombination of capacitor and primary winding forming a passiveswitchless network; (c) discharging said primary winding and capacitorduring the other half of said cycle; and (d) creating igniter firingenergy by effecting a plurality of steps (b) and (c) during eachignition period.
 8. The method as stated in claim 7, including thefurther step of:(e) generating an electrical arc between an electricallyconductive tubular base and an electrode of an igniter, said arc havinga filament of luminous particles extending between said base andelectrode and a mass of luminous particles of lesser density than saidfilament which surrounds said filament.